Electric and plug-in electric vehicles require an interface to external charging devices. In order to promote standard interfaces among vehicle and charge station manufacturers, industry standards have been developed. One such standard is the SAE Electric Vehicle and Plug in Hybrid Electric Vehicle Conductive Charge Coupler (J1772) standard. The J1772 standard defines a charge coupler and the associated protocol required for transferring energy to the vehicle. The standard defines a common interface that all vehicle and charge station manufacturers are encouraged to follow.
A plug-in hybrid or electric vehicle connects to electric vehicle supply equipment (EVSE) to charge a traction battery. A DC-DC converter switchably connected to the traction battery through a contactor provides power to an auxiliary battery during charging. In order to provide power to the auxiliary battery, the voltage of the traction battery must be supplied to a high-voltage bus.